While attention during this year's World Cup was focused on upsets and major clashes on the pitch, a different battle was unfolding on prediction markets.
The Group of Copenhagen, an international organisation focused on integrity in sport, identified seven suspicious bets on prediction platforms, including Polymarket, which it says may be linked to the manipulation of sporting events.
The full report has not yet been published. According to sources cited by The Athletic, one of the suspicious cases involved wagers worth nearly $4.8 million on Polymarket predicting that Spain would not beat Cape Verde. The match ended in a 0-0 draw, one of the biggest surprises of the opening round.
Another bet that raised suspicions was titled: "Will Folarin Balogun play against Belgium?" It was placed on 2 July, the same day the United States striker was sent off with a red card in a match against Bosnia and Herzegovina.
A player shown a red card is automatically suspended for his team's next match. In this case, the United States' next game was against Belgium.
However, in a development that later drew significant criticism, FIFA's Disciplinary Committee took the unprecedented step of suspending Balogun's punishment and allowing him to play in the next match.
The decision was announced on 5 July.
It later emerged that the ruling had been made after US President Donald Trump personally contacted FIFA President Gianni Infantino to complain about the American player's dismissal.
Trump later described the suspension of Balogun's ban as an "excellent decision".
Adding to the suspicions, sources told The Athletic that, according to the Group of Copenhagen report, no bets were placed on any of the other 14 players sent off during the World Cup.
FIFA found no evidence
FIFA's Integrity Task Force has taken a different view.
In a report published on 22 July, it said it found no indication of unlawful activity.
According to The Athletic, the report concluded that there had been "no suspicious betting activity or indication of match manipulation in any match".
Insider trading?
The Group of Copenhagen, however, said it identified seven "yellow notices" relating to bets connected with the 2026 World Cup.
According to the organisation, such notices are issued when there are signs such as unexplained odds movements, rumours circulating on social media or information obtained from sources.
Within the body's alert system, a yellow notice precedes orange and red alerts, with red representing the highest level of concern.
No specific accusations have been made at this stage.
However, the Balogun bet could be viewed as a sign of possible exploitation of inside information.
The Trump administration has already faced similar controversies involving prediction markets.
Among them is the case of a White House employee who is under investigation after allegedly making more than $100,000 betting on the Kalshi platform on events related to Trump's speeches.
Alternative explanations
According to Christian Kalb, a betting industry expert who has previously worked with the Group of Copenhagen, the bets may have been flagged for reasons other than match-fixing.
He said platforms such as Polymarket may be used by bookmakers for hedging purposes, which may have been the case with betting activity surrounding the Spain-Cape Verde match.
"If you're a traditional bookmaker, there will be matches where almost everyone is betting on the clear favourite," Kalb said.
"From the bookmaker's perspective, that can create excessive exposure to a particular outcome. If it's a small company, that can represent a significant risk. In that situation, it may use a prediction market such as Polymarket to hedge that risk."
